Subflooring thickness

[Dstrnad]

Any input on subflooring thickness. Floor joists 16"oc I am using eastern white pine it is just the subfloor and will be covered with hardwood. At first I was going to use 4/4. I have been thinking of cutting on 1" minus kerf, after drying, light plane on one side should be close to a finished 3/4" then t&g?

Thanks
Dave

[GeneWengert-WoodDoc]

The following link gives great info on selection of underlayment and subflooring.
http://www.tecotested.com/techtips/pdf/plywooddesignapplicationguide

I personally like the combination of subfloor and underlayment.

Another link is
http://www.installfloors.org/FloorSubfloor.xml

[dgdrls]

typically see 3/4" T&G ply for sub-floor with 16" OC joists.

not certain on how much WP deflects Vs. 3/4" ply.

what does local building code call for?

DGDrls

[millwright]

3/4 is pretty much what is used in this area, it is usually laid diagonaly across the joists.

[Texas Ranger]

I used 1 1/8 4x8 sheets of T&G subfloor.  Stout.

[Chuck White]

I would saw out some 5/4, dry it, then plane it to 1-1/8".

Installation would be diagonal, 45°!

[bandmiller2]

Alot depends if your trying to match outher rooms floor hight.Also what your using for hardwood flooring that thin modern 6!@#%^&* their selling needs real underlayment.The real flooring you don't even have to plain.Id screw it down good with drywall screws mayby even liquid nails too. Frank C.

[Holmes]

 If you are putting an additional 3/4 " floor on top of the sub floor ,3/4 underlayment will be fine or just under 1" as you were thinking of doing.  Years ago 1/2" plywood underlayment with 3/4" hardwood on top was legal now it's not.

[Dstrnad]

Thanks for the replys. Code calls for a min 11/16" for 24"o/c 5/8" for 16" o/c when using lumber. It also does not have to be t&G. I want to t&g and glue it to help prevent squeky floors. Do you think that makes sense? It does not have to be t&g, but it seems like I have seen where the boards rub when they are just butted.  If I ommitted the subfloor I would go with a heavy 1" finished, but I think it would be too hard to build without damaging the floor and the transition between other flooring becomes tricky.  Thanks

[Magicman]

I used 1" non T&G sub flooring over 2X12 with 16" o/c on mine.  If I possibly had two board edges rubbing together and causing a squeak, then I could crawl underneath and relieve it.  The flooring is 15/16" T&G.  I see no way short of driving a dozer across it that it would give enough to ever squeak.

Of course I have no code, and as usual, I am flying by the seat of my pants.   ;D 

[rooster 58]

    Also using a coated, ringshank nail will help prevent loose, squeaky boards. Glue as well ;)

[Peder McElroy]

I agree with Magicman.

[red oaks lumber]

just use a sqaure edge board, use a finish nail as a spacer that way you wont have any possible" sqeakers'.just a thought

[Dstrnad]

Magic Man,

Did you use all the same width boards? I was going to use 1"x12"

[duke]

 Up in Canada the norn before the use of plywood was 3/4" x 6" or 8" Douglas Fir or Hemlock shiplap run on the diagonal over 16" O/C Fir/ Hemlock floor joists. That was houses built about 1910 and newer. Though some had 1" material rough sawn and its use was mainly to save money on Planing and machining or just no planer mill close enough to be cost effective.
That's my 2 cent's, oh and Canada no longer has the Pennie or 1 Cent  :'( :'( :'( :( ??? ??? This saves the Government seven million a year on a 26 BILLION DOLLAR DEFFICET. WOW am I impressed, NOT. :D :D :D
duke

[Magicman]

I used 1X6's but that was because it was easier to get them from my available logs.  I see no reason why any width or even a variety of widths could not be used.  The original part of my Cabin is sub floored with 1X12's.

ROL's spacing as described above is standard procedure.  I did not space because I knew that I would still have some shrinkage. 

[rooster 58]

    If you use 1x12's you will undoubtedly have shrinkage, so I would nail them tight

[rimshot]

Built a house out of entirely rough sawn out door dry lumber back in 1977.  I sized joist to 7 3/4" width so they were all the same.  Cut spruce into 1X6" & 1 X 8" subfloor sheeeting and planed one side to 7/8" thickness to make it all the same.  Ran it at a 45* angle and covered it all with 15 # tar paper.  It proved to be one of the quietest and squeak free floors I ever built.  Floor joists ran two directions.

rimshot

[Dstrnad]

Well I started cutting floor sheeting, that is after cutting the boy several small logs for his fort. In all I cut about 300 bdft, it went pretty well. The need for log handle equipment was obvious on the 12' 18" log. Untill today all I cut was small 10" red pine. I like cutting the larger logs goes pretty quick, I think it took me longer to get the log on the mill then to cut it.

Dave

[rimshot]

I believe I even glued the spruce sheeting to the joists and then I added 5/8 underlayment with lots of #8 ring shanks.  he sheeting was laid tight edge to edge and shrunk back just enough to provide for not a squeak.  Make sure your joists are the same width exactl. 

rim

[Dstrnad]

I think I am going to cut the floor joist with an additional 1\2 inch then true them with the sawmill in bunches after they dry. So I will cut them 10 1\2 for a finish of 9 1\2. This should give me a nice even floor without much crown.

[rimshot]

I take it that it's ok with the buiding inspector and he will allow the rough lumber and probably not graded stuff instead of stamped store bought?

rim

[Magicman]

With your floor joist, just measure from the top edge.


 
Any difference in width will be inconsequential.


 
Here I used 2X12 joist with a doubled 2X10 band.


 
Here the 2X10 band is being doubled.


 

[Dstrnad]

Rim,
The inspector does not have a problem with it here in my county and even if he did it is my understanding that all you have to do is have an engineer review it. This seems to be less of a hassle then using a lumber grader. I'm still fuzzy on the whole thing but I have found someone to approve my plans if needed. I hope I am not wrong.

Magic Man,
Nice looking project, good idea I will keep that in mind.

[rimshot]

Magicman,

That is a good idea......just measure down from top and mark a notch if need be and cut a notch.  Never occurred to me but if he  happens to be doing joists for a second level he might need to rip the whole joist for the sake of truing up the ceiling.

Dstrnad
I believe code for the state requires that a certified lumber grad  er has to examine the building lumber and all the requirements for that title  are something like a two day course for counting knots.  County extension needed but can help you with that problem if need be.  No engineer required.  You are right about needing an engineer for the building project blue print or plans, it requires an engineer  stamp.

As always, the local building inspector makes the final call.  If you happen to think the rule smells I would agree.



 

rim